Ibn al-Qayyim (rahimahullaah) said:
وأصل المعاصي كلها العجز ، فإن العبد يعجز عن أسباب أعمال الطاعات ، وعن الأسباب التي تُبعده عن المعاصي ، وتحول بينه وبينها ، فيقع في المعاصي.
The foundation of all disobedience (sins) is incapacity. For the servant is not able (to take) the ways (leading to) actions of obedience and the ways that distance him from sins, (which) come between him and them. Hence, he falls into sins, thereby.
In Zaad al-Ma'aad (2/362). Note: Being unable to take the ways and means is a deficiency and fault on behalf of the servant, indicating a weakness in his resolve and intent (iraadah, qasd, 'azm). This underlies his falling into disobedience.
Translated by Abu Iyaad (@abuiyaadsp)